To provide a navigation system for receiving VICS data without any loss even if a DGPS is not able to receive data temporarily due to the failure in a reception state when performing the reception of VICS and DGPS by time sharing using one FM multiple receiver.

When the reception state of a FM multiple broadcasting station for transmitting DGPS data is poor in detection by a DGPS data reception state detection means, the VICS data are received preferentially, thus preventing the VICS data from lacking due to the time-sharing reception of the DGPS and VICS, and hence reducing the amount of processing of a control means that is normally composed by a microcomputer or the like for controlling the time-sharing reception of the FM multiple broadcasting reception means, and hence distributing the received amount of processing to other controls.